<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <script src="./jquery.js"></script>
    <style>
        .add{
            font-size: 30px;
        }
    </style>
</head>

<body>
    <div id="liYangLong">你真是个天才</div>
</body>

</html>
<script>
    var tools = {
        fn:function(){
            $('#liYangLong').css('background','red')
            return tools
        },
        fn1:function(){
            $('#liYangLong').addClass('add')
            return tools
        },
        fn2:function(){
            $('#liYangLong').click(function(){
                alert('总能带来点惊喜')
            })
        }
    }
    tools.fn().fn1().fn2()
</script>